The present invention relates to a dyeing apparatus for carrying out laboratory tests, as well as to the dyeing method used.
As known, the purpose peculiar to laboratory dyeing tests is that of obtaining, on few grams of textile support (5/20 gr.) a dye that can be 100% industrially reproduced.
In these tests, the most difficult parameter to obtain is that of a perfect homogeneity of the dye.
The latter refers not just to an even visual appearance, but also particularly to the homogeneity in the thickness of the textile support (fabric or yarn).
Even more relevant difficulties are to be found in especially firm fabrics.
It is obvious that an even superficial appearance, which is not homogeneous in its thickness, implies a series of disadvantages causing a precarious and expensive exploitation on an industrial scale.
An object of the present invention is to eliminate the disadvantages previously reported, by providing a dyeing apparatus for carrying out laboratory tests allowing even coverage of the fabric or yarn sample so as to obtain especially homogeneous dyeing conditions, reproducible in the industrial process.
A more specific object of the invention is to provide a method which can accurately reproduce the industrial dyeing steps, by operating on a fabric or yarn that needs not be wound on a support core, and which is thus evenly covered by the dyeing bath. Another object of the present invention is to provide a dyeing apparatus which is capable of guaranteeing great reliability and safety of use.
A further object of the present invention is to provide an apparatus and a method allowing the fabric or yarn to be arranged in a plane and even form so as to be covered by the dyeing bath throughout its thickness thus affecting to the same extent both superficial and internal parts.
Still another object of the present invention is to provide a dyeing apparatus which is easily obtainable starting from elements and materials that are commonly available on the market and is, in addition, competitive from a purely economic point of view.
The aforementioned objects and others that will appear more clearly hereinafter, are achieved by a dyeing apparatus for carrying out laboratory tests, according to the invention, which comprises a dyeing chamber which can be sealingly coupled to at least one portion of the fabric to be dyed, and means for displacing the dyeing liquid carrying out a sequence of alternate passages of the dyeing liquid through the fabric to be dyed.